Effects of sleep loss on confidence-accuracy relationships for reasoning and eyewitness memory

Participants (n = 48) deprived of sleep for 29-50 hr, in comparison with co ntrols (n = 45), underestimated their performance on logical reasoning and Raven's matrices. Such caution may ameliorate adverse practical consequence s of sleep loss. In contrast, although sleep loss participants were more su ggestible on the Gudjonsson Suggestibility Scale (G. H. Gudjons son, 1984, 1987), they maintained confidence in their suggestible responses and were i naccurate when responding with the highest rating of confidence. This indic ates that the increased suggestibility is internalized and is due to a cogn itive deficit rather than to compliance. Eyewitness confidence-accuracy cor relations were low but usually significant and were lowest after 47-50 hr o f sleep loss. Repetition of leading questions led to increases in confidenc e for suggestible responses (with no interaction with sleep loss) but not f or nonsuggestible responses, indicating a problem for jurors' evaluations o f practiced testimony.